In 2008, CIA head Michael Hayden told Congress it had only been used on three high-profile al-Qaeda detainees, and not for the past five years.

One of those was Khalid Sheikh Mohammed, a key suspect in the 9/11 attacks, who was reportedly waterboarded 160 times.

Mr Rove said US soldiers were subjected to waterboarding as a regular part of their training.

A less "constrained" form of the technique was used on the three suspects interrogated at the US military prison at Guantanamo Bay, he said.

"I'm proud that we used techniques that broke the will of these terrorists and gave us valuable information that allowed us to foil plots such as flying aeroplanes into Heathrow and into London, bringing down aircraft over the Pacific, flying an aeroplane into the tallest building in Los Angeles and other plots," Mr Rove told the BBC.

"Yes, I'm proud that we kept the world safer than it was, by the use of these techniques. They're appropriate, they're in conformity with our international requirements and with US law."

Mr Rove has just written a memoir, Courage and Consequence, in which he defends the two terms of the Bush administration as "impressive, durable and significant".

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